Comment # 1 on bug 1171368 from Michel Normand

Created attachment 837550 [details]
y2log_boo1171368.log

same problem with manual test, and able to capture y2log as
y2log_boo1171368.log
with following extract:
===
2020-05-07 13:15:01 <1> install(2989) [Interpreter] clients/installation.rb:93
Calling YaST client inst_worker_initial
2020-05-07 13:15:01 <1> install(2989) [Ruby] yast/wfm.rb:313 Call client
/mounts/mp_0001/usr/share/YaST2/clients/inst_worker_initial.rb
2020-05-07 13:15:01 <2> install(2989) [Ruby] yast/builtins.rb:586 tostring
builtin called on wrong type Class
2020-05-07 13:15:01 <3> install(2989) [Ruby] yast/wfm.rb:253 Client
/mounts/mp_0001/usr/share/YaST2/clients/inst_worker_initial.rb failed with
'cannot load such file -- storage' (LoadError).
Backtrace:
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/share/YaST2/lib/y2storage/storage_class_wrapper.rb:20:in
`<top (required)>'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/share/YaST2/lib/y2storage/bcache.rb:20:in `<top
(required)>'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/share/YaST2/lib/y2storage/devicegraph.rb:22:in `<top
(required)>'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/share/YaST2/lib/y2storage.rb:20:in `<top (required)>'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/share/YaST2/include/installation/inst_inc_all.rb:30:in
`<top (required)>'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in
`require'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/yast.rb:135:in `include'
/mounts/mp_0001/usr/share/YaST2/lib/installation/clients/inst_worker_initial.rb:53:in
`main'
/mounts/mp_0001/usr/share/YaST2/clients/inst_worker_initial.rb:2:in `<top
(required)>'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:318:in `eval'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:318:in
`run_client'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:206:in
`call_builtin'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:206:in
`call_builtin_wrapper'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:195:in
`CallFunction'
/mounts/mp_0001/usr/share/YaST2/lib/installation/clients/installation.rb:93:in
`main'
/mounts/mp_0001/usr/share/YaST2/clients/installation.rb:2:in `<top (required)>'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:318:in `eval'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:318:in
`run_client'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:206:in
`call_builtin'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:206:in
`call_builtin_wrapper'
/mounts/mp_0001/usr/lib64/ruby/vendor_ruby/2.7.0/yast/wfm.rb:195:in
`CallFunction'
/usr/lib/YaST2/bin/y2start:60:in `<main>'
===